alter_domain - phpMan

ALTER DOMAIN()                   SQL Commands                   ALTER DOMAIN()



NAME
       ALTER DOMAIN - change the definition of a domain


SYNOPSIS
       ALTER DOMAIN name
           { SET DEFAULT expression | DROP DEFAULT }
       ALTER DOMAIN name
           { SET | DROP } NOT NULL
       ALTER DOMAIN name
           ADD domain_constraint
       ALTER DOMAIN name
           DROP CONSTRAINT constraint_name [ RESTRICT | CASCADE ]
       ALTER DOMAIN name
           OWNER TO new_owner
       ALTER DOMAIN name
           SET SCHEMA new_schema



DESCRIPTION
       ALTER  DOMAIN changes the definition of an existing domain.  There are several sub-
       forms:

       SET/DROP DEFAULT
              These forms set or remove the default value for a domain. Note that defaults
              only apply to subsequent INSERT commands; they do not affect rows already in
              a table using the domain.

       SET/DROP NOT NULL
              These forms change whether a domain is marked to allow  NULL  values  or  to
              reject  NULL  values.  You  can only SET NOT NULL when the columns using the
              domain contain no null values.

       ADD domain_constraint
              This form adds a new constraint to a domain using the same syntax as  CREATE
              DOMAIN  [create_domain(7)].  This will only succeed if all columns using the
              domain satisfy the new constraint.

       DROP CONSTRAINT
              This form drops constraints on a domain.

       OWNER  This form changes the owner of the domain to the specified user.

       SET SCHEMA
              This form changes the schema of the domain. Any constraints associated  with
              the domain are moved into the new schema as well.

       You must own the domain to use ALTER DOMAIN.  To change the schema of a domain, you
       must also have CREATE privilege on the new schema.  To alter the  owner,  you  must
       also be a direct or indirect member of the new owning role, and that role must have
       CREATE privilege on the domain's schema. (These restrictions enforce that  altering
       the  owner  doesn't  do  anything  you  couldn't  do by dropping and recreating the
       domain.  However, a superuser can alter ownership of any domain anyway.)


PARAMETERS
       name   The name (possibly schema-qualified) of an existing domain to alter.

       domain_constraint
              New domain constraint for the domain.

       constraint_name
              Name of an existing constraint to drop.

       CASCADE
              Automatically drop objects that depend on the constraint.

       RESTRICT
              Refuse to drop the constraint if there are any dependent  objects.  This  is
              the default behavior.

       new_owner
              The user name of the new owner of the domain.

       new_schema
              The new schema for the domain.


NOTES
       Currently,  ALTER  DOMAIN ADD CONSTRAINT and ALTER DOMAIN SET NOT NULL will fail if
       the named domain or any derived domain is used within a  composite-type  column  of
       any  table in the database. They should eventually be improved to be able to verify
       the new constraint for such nested columns.

EXAMPLES
       To add a NOT NULL constraint to a domain:

       ALTER DOMAIN zipcode SET NOT NULL;


       To remove a NOT NULL constraint from a domain:

       ALTER DOMAIN zipcode DROP NOT NULL;



       To add a check constraint to a domain:

       ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5);



       To remove a check constraint from a domain:

       ALTER DOMAIN zipcode DROP CONSTRAINT zipchk;



       To move the domain into a different schema:

       ALTER DOMAIN zipcode SET SCHEMA customers;



COMPATIBILITY
       ALTER DOMAIN conforms to the SQL standard, except for  the  OWNER  and  SET  SCHEMA
       variants, which are PostgreSQL extensions.

SEE ALSO
       CREATE DOMAIN [create_domain(7)], DROP DOMAIN [drop_domain(l)]



SQL - Language Statements         2009-03-12                    ALTER DOMAIN()

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